Quantum behavior of Orbitals in Ferromagnetic Titanates: Novel Orderings and Excitations

الأصل · EN

We investigate the collective behavior of orbital angular momentum in the spin ferromagnetic state of a Mott insulator with t₂g orbital degeneracy. The frustrated nature of the interactions leads to an infinite degeneracy of classical states. Quantum effects select four distinct orbital orderings. Two of them have a quadrupolar order, while the other states show in addition weak orbital magnetism. Specific predictions are made for neutron scattering experiments which might help to identify the orbital order in YTiO₃ and to detect the elementary orbital excitations.